So a few months back i decided to build my own snake rack for the 8 hatchlings i took on - but i was on a budget! I spent less than £60 in total!
I first took a set of shelves i happened to be given by someone, though you can buy these for around £15 in charity shops or second hand furniture sales - the snake doesn't care who it used to belong too! Mine had an open back for easy wiring, had 6 shelves, measured 58 inches high with a shelf height of 9.5", depth of 7" and width of 23.5"
I decided to use heat cable for its versatility so i placed down aluminium tape down in lines to protect the wood and reflect the heat up. I bought 10m of tape on ebay for £4. I then placed the heat cable looped on top, fixing it in place with more aluminium tape (Don't let the wire cross itself). I bought 7m for £16 through swell reptiles and it covered 3 out of my 6 shelves using 3 loops or 5 shelves using 2 loops. You could buy garden propagation cable cheaper though if you hunted around. I used a thermostat to control it that cost £19 via swell reptiles, though you could find one cheaper on ebay most likely. I bought a lucky reptile thermometer with two probes for £6 off ebay to measure temperatures with (currently around 31c in the hot end).
I then prepared the actual RUBS. I went to poundland and bought nine 7 litre Rubs (for £9 naturally). I then used a screw to make air holes in the sides and the lid. I also got 10 plastic small plant pots for £1 at poundland and cut in an entrance hole to make them into hides. You can also get 3 ceramic small ramekin bowls that make great water dishes or 4 stainless steel bowls for £1 at poundland. I use the ramekin bowls which cost me £3. I then added my tubs. They hang off the back sightly, but i dont mind this since it helps keep the cool side cool. I bought three tubs that were not as tall as the others since the lids could overlap slightly and i can fit more on the shelves. I also added once 'dud' tub that has a tight fitting hole cut in and the probes for the thermostat/thermometer placed in. This gives me a good reading of what the temperature inside is like without having to risk snake escapes! If you want you can purchase individual thermometers for each tub for around £2 on ebay. I chose not too. I also strung some string up in their enclosures through two extra air holes with a toiletroll tube threaded on to make a tube-hammock. They adore them and they spend time hiding in it, climbing on it and sitting under it. If they poop in it - its just a loo roll!
Initially for substrate i used paper towels, but now they're around 6 months i felt it was time for a substrate that allowed burrowing. I like the cardboard based substrates like finacard, but it's expensive for the amounts i'd need. Then it hit me - i have a shredder and me/my housemates buy a lot of things we need online which comes in copious amounts of cardboard. I personally only use the brown cardboard of the interior/plastic wrapped packaging and as im doing it on a personal basis i check over each piece before i shred it. The best part is i can control the size of the pieces, its surprisingly soft, absorbent and easy to clean. I offer them a space that has no card and one sheet of kitchen roll folded over and they can use that if the card bothers them at all (it doesn't - they love burrowing in it!)